The catalytic reactor conventionally comprises a plurality of reactor modules which are arranged one above the other and in which the reactor bed is arranged horizontally, wherein flow then proceeds through the reactor beds in a vertical direction, in each case starting from the associated gas distribution chamber towards the associated gas collection chamber.
Between the individual reactor modules, the process gas is discharged from the catalytic reactor in order to permit temperature regulation and/or further chemical conversion processes.
Multistage catalytic reactors for converting SO2 into SO3 in the production of sulfuric acid are also known in the industry as contactors.
It is precisely in the large-scale industrial production of sulfuric acid and fuming sulfuric acid that stringent requirements arise purely due to the conventional volumes involved in the oxidation of sulfur dioxide to sulfur trioxide. Accordingly, catalytic reactors for producing 2000 tonnes of sulfuric acid per day are for example known in practice which have a height of approx. 23 m, a diameter of approx. 11.5 m and a weight of approx. 330 tonnes. The material used here is high temperature-resistant special steel.
Unwanted emissions of sulfur dioxide from the sulfuric acid production plant are essentially determined by the extent to which the catalytic conversion of sulfur dioxide to sulfur trioxide proceeds to completion in the multistage contact tower. According to the German Guideline, Technical Directions for Air from 2002, catalytic conversion must be greater than 99.8% and, according to stricter guidelines, even greater than 99.9%. Maximally complete catalytic conversion is thus not only desirable on economic grounds but also frequently necessary in order to comply with environmental requirements. It must also be borne in mind that the degree of catalytic conversion may also vary as a function of the capacity utilization of the catalytic reactor.
Due to the typical size of the catalytic reactor, the simplest possible design should also be used which permits straightforward assembly on site and minimizes material consumption.
A catalytic reactor, specifically a multistage contact tower for converting sulfur dioxide into sulfur trioxide in the production of sulfuric acid according to the preamble of claim 1 is known from WO 86/03187 A1. In particular when such a plant is operated under part load, the efficiency of catalytic conversion is frequently not sufficient to meet stringent legislative requirements.
According to a fundamentally different approach to design, multistage contact towers are known in which gas distribution proceeds through a central pipe. Such a contact tower exchanger is known from DE 23 37 958 A1. The design does, however, suffer the disadvantage of being relatively complex and thus costly to produce and assemble.
Thus a need exists for a catalytic reactor, in particular a multistage contact tower for converting SO2 into SO3 in the production of sulfuric acid which is distinguished by both particularly efficient catalytic conversion and a simple design.